Many types of fasteners require a specific torque range to be applied to insure properly setting the fastener. To assist in this there are winding tools that are set to apply a specific shut-off torque, and on some of the machines the shut-off torque may be adjusted within a specific range. One such tool is a nutrunner. On the adjustable nutrunners the desired torque is set and the unit will stop when that set torque is reached. Normally the nutrunners use a torque sensitive mechanical clutch which trips out when the torque setting is reached. Unfortunately, mechanical clutch nutrunners are in general especially sensitive to the "Joint Rate" of the fastener certification device which is used to adjust this clutch. This "Joint Rate" is defined as the energy absorption capability of the particular joint into which a fastener is installed. A particular nutrunner set to one torque will give a good solid join to a fastener used on a joint having one particular "Joint Rate" and will give an unsatisfactory join to a fastener having a different "Joint Rate."
It was found that a fastener certification device that is adjustable to reflect different absorption capability for a range of joints may be used to check on and to obtain the optium torque setting on a torque controlled winding tool that will insure a properly secured fastener regardless of the "Joint Rate."